Received this card like a week ago, but had some problems with it not fitting inside my case, problems that are luckily solved now. Yet there appears to be a bus interface problem now, let me describe it.

Notice how the Bus interface says "PCI-E 2.0 x16 @ x4 2.0" on first and "PCI-E 2.0 x16 @ x8 2.0" on second.
I first thought this was a power-saving feature so I run the "render-test" available if you click the ? next to the bus interface specs, but neither the x4 nor the x8 would go up to x16 after 10 minutes of testing and I found other people's gpu-z 5970's screenshots on the internet that do show x16. Both Trixx and CCC show x4, although CCC also specifies that the max bus setup is x8.

Notice how my motherboard has only one pciex16 slot, as the second one is a pciex16 running at x4. But that's not the issue as the card is plugged into the pciex16 one. Yet it's not a motherboard issue, as I have a Sapphire HD 6870 that I've tried and its bus interface value is correct: PCI-E 2.0 x16 @ x16 2.0.
My bios version is F7, it's the one that came with the rev 1.2 of it and the last one available before the F8a, which is a beta bios. So I don't really want to upgrade it to the beta one.Init Display First was set to PCI Slot by factory default so I switched it to PEG to see if that would change anything. Before you ask, the card was already running on M.x4 & S.x8 with the PCI option, and it's still the same with PEG.

Tried cleaning both card socket to the mb and the mb socket itself with isopropyl, as it has helped me some time before with my RAM issues. Nothing.

Also, I'm currently using the 13.9 WHQL drivers (did a clean install, using guru3d DDU), as the 13.11 betaV9.2 ones were giving me screen artifacts and controller hangups every 3-5 minutes, and even BSODs. Had these driver issues only with the 5970, as the 6870 is working perfectly.

Here's the rarest thing, though. I tried running Furmark (Full-screen, Benchmark preset:1080) and I get around 3530 points (score link) which is around the same that other people get with their 5970 so there's kind of no performance issues, despite the x4. Results show one gpu only though, and I don't know if it's an issue, as this is a dual gpu card; opinions on this?

My only choices, known for me that is, left are:
- updating my gpu bios to the one known best for fixing all the problems, this one. I read that my current one is known for being a buggy one, but I know if that will fix my x4 issue. If I end up doing it, which I don't really want to, should I do it with atiflash & msdos or through atiWinflash?
- reverting my catalyst drivers to something even more stable, something like 13.1 or 13.2, as the gpu-z photos I've seen that had x16 were using those.
- trying with a different PCI-E connectors or even a different PSU. My PSU is modular, so PCI-E connectors can be changed, to see if there's a power supply issue (5970 eats around 294W, whilst the 6870 is only about the half, so maybe that's why I see no issues with its x16 against the 5970's x4?). A friend of mine might be able to lend me his 750W psu, to see if the issue is my psu itself.

I think that's about it, any suggestions and/or help will be sincerely appreciated. Thanks in advance

-Test the vga card in another system on a different motherboard model
-Use older version of GPU-Z 0.5.9 [should be in the TPU archives]
-Clean the vga cards PCIe blades with a coffee filter and isopropyl alcohol
-Clean the PCIe x16 slot with a air duster
-Reseat the vga card, double check that there are no obstructions and the card fits
-Double check power cable are secure and that the PSU is ouputing the required AMP [75w six & 150w eight pin power]
-Do not use furmark to test the card as it may harm it; [instead use a game to place load on the card] or use GPU-Z "? icon" to check the PCIe bus speed.

I was about to make a backup of both bios files and when I switched to do the slave one I noticed that now its bios is OC8, same as the Master one. While yesterday, if you check the links at my first post, it was at OC9. Screenshots were done in idle mode yesterday, so I don't think this is due to a different bios profile, is it?

Already cleaned it as much as I could before, but with cotton swabs soaked in isopropyl as I don't have a compressed air bottle. Will try getting one for further cleaning, but the 6870 is running great at x16, no problems whatsoever with that one, just with the 5970.

-Double check power cable are secure and that the PSU is ouputing the required AMP [75w six & 150w eight pin power]

Click to expand...

Yeah, as the PSU is modular I thought some of the cables wouldn't be seated perfectly or something, but turns out they are. How do I check the output though? Can it be checked with software or only with a tester?

Just commenting to follow the thread. I'm interested to see how this develops. Before you do anything too crazy, check to see if the card is still under warranty. If it is, don't touch it and contact support.

If I'm not mistaken, and I'm drawing from a general understanding of dual-gpu cards and not from knowledge of this card specifically, there should be a chip on the card that splits the 16x PCI-E 2.0 in to two 16x slots. It's typically near the PCI-e pins. (Found a picture of it here)
To quote hothardware's review on this card, "The Radeon HD 5970 architecture is much like previous X2 cards. Each of the card's GPUs are linked together on a single PCB, via a PLX PCI Express 2.1 Gen 2 bridge."

I would suspect any issue with the negotiation of the two GPUs would be due to that bridge. It might be worth checking around in your motherboard to see if it tells you the link between chipset and PCI-e bridge is running at (likely 16x). If you don't mind taking the cooler off, check the back of the card for physical damage. There may be something shorting out some of the pins.

The solution to this, I'm afraid to say, is beyond me. Flashing a BIOS may not help unless there's a weird incompatibility between some BIOSes and the bridge on their own card, which there could be.

I was about to make a backup of both bios files and when I switched to do the slave one I noticed that now its bios is OC8, same as the Master one. While yesterday, if you check the links at my first post, it was at OC9. Screenshots were done in idle mode yesterday, so I don't think this is due to a different bios profile, is it?

Click to expand...

Create a bootable flash drive with atiflash use version 3.79 from here change settings in mobo bios to boot from USB, run atiflash at the DOS prompt; type the following:

atiflash -ai 0 [look at the adapter information] = Master

atiflash -ai 1 [look at the adapter information] = Slave

atiflash -s 0 MasterOld.rom [will make a backup of the master]

atiflash -s 1 SlaveOld.rom [will make a backup of the slave]

Use RBE 1.28 to look at the versions and double check OC8 & OC9 [vga card cannot change this it's self but may be corrupted]